The invention relates generally to ground vehicles and, more specifically, to a lift apparatus for ground vehicles which utilizes a four-bar linkage.
Land vehicles are, of course, in very common usage. Certain or such vehicles, particularly tractor-drawn agricultural implements, must be height-adjustable relative to the ground so that they can function effectively and efficiently. By way of specific example, balers of crop material must have sufficient ground clearance to allow transport through the crop field and yet also have a crop pick-up mechanism that is adjustable to operate adjacent the surface of the ground so as to engage and pick up the crop material to be baled.
In existing balers, such as are described in U.S. Pat. No. 4,172,354, the height of the main body of the baler above the ground is fixed and the crop pick-up mechanism is raised and lowered relative to the rest of the baler to the operating or transport position. The above-identified baler is of the "open throat" design which includes a bale starting chamber the entrance to which is defined by the crop pick-up mechanism and a starter roller. The size of this opening changes with adjustments in the position of the crop pick-up mechanism relative to the baler. Because the operation of the bale starting chamber is sensitive to the size of the opening to the chamber, movement of the crop pick-up mechanism can, under certain circumstances, adversely affect the performance of the baler. There is a need, accordingly, for a baler with a lift apparatus whereby an operator can quickly and easily adjust the height of the baler and the associated crop pick-up mechanism without changing the size of the open throat entrance to the bale starting chamber.